The FAA this week became aware that Allegiant Air may not have inspected some emergency evacuation slides on its MD-80 fleet at required intervals. The agency learned about the issue while investigating an emergency evacuation of Allegiant Airlines flight 436 at McCarran International Airport on September 16, in which all passengers were safely evacuated. The agency directed Allegiant to immediately report the inspection status of all slides installed on its MD-80 fleet.

McCarran is the Las Vegas airport.

ORIGINAL ITEM: Allegiant Travel said early Friday (Dallas time) that it has launched an “immediate inspection of many slides in its MD-80 fleet” and will have to cancel flights until it completes the process.

Said Allegiant:

The Company has already begun the reinspections and expects to complete the process by the end of September. MD80 aircraft will be placed back in service as soon as possible after the slides pass reinspection. In the meantime, Allegiant will take as many as 30 MD80s out of service and delay, reschedule or cancel a number of flights over the next several days.

“We apologize for the disruption to our passengers and ask that they please remain patient as we work to correct the issue, reschedule affected flights and accommodate any passengers impacted,” Allegiant Travel president Andrew Levy in the company’s late night press release..

“Allegiant is committed, above all else, to the safety of our passengers and crew, and we are dedicated to working around-the-clock to ensure that all of our fleet meets the highest standards,” he said

Allegiant is a Las Vegas-based company that charges low fares with few free amenities. It offers vacation travel from a lot of smaller cities to Las Vegas, Hawaii, Florida and other leisure destination. It does not serve Dallas/Fort Worth International Airport.

Its fleet is made up primarily of the McDonnell Douglas MD-80 type, with 56 of them as of June 30. Their average age is about 24. Allegiant also operates six Boeing 757s and two Airbus A319s.

As of 10 a.m. Dallas time, FlightStats.com hadn’t recorded any Friday cancellations for the carrier. At that point, it had had 12 departures out of 113 scheduled for the day. We’ll see how it develops as the day goes on.

With JetBlue Airways’ filing of its December and full year traffic on Friday, we’ve got all the big carriers reporting. Here are some observations (revised Monday, Jan. 14, 2013, after Spirit Airlines reported its December and full year numbers):

– The four largest carriers – United Airlines, Delta Air Lines, American Airlines and Southwest Airlines – all operated less capacity in 2012 than in 2011. The next five carriers increased their capacity.

– United, the world’s largest airline, saw its margin in traffic over No. 2 Delta shrink. In 2011, it led Delta by 13.48 billion revenue passenger miles. In 2012, the lead dropped to 9.85 billion. Put another way, it was 8 percent larger than Delta in 2011, 5.8 percent larger in 2012.

– In capacity, United had a lead of 15.99 billion available seat miles in 2011, 15.48 billion in 2012. United was 7.9 percent larger than Delta in capacity in 2011, 7.7 percent in 2012.

– You may have noticed that the gap shrank more quickly in traffic than capacity. That would indicate that Delta was showing better results on load factor.

– In fact, Delta’s load factor went up 1.7 points to 84.4 percent. United’s went up 0.1 points to 82.9 percent. (United was 0.1 point ahead of Delta in 2011, 1.5 points behind in 2012.)

– Overall for U.S. carriers, traffic in revenue passenger miles and absolute passengers increased only about 1.3 percent in 2012 over 2011.

– Capacity in available seat miles was up less, 0.4 percent, helping the carriers show a 0.7 percentage point increase in load factors, to 83.0 percent.

Here are the charts for the U.S. airlines that we have in hand. Traffic is thousands of revenue passenger miles; capacity is thousands of available seat miles. We put full year results first, followed by December’s results.